3Robert F. Speyer, Elizabeth A, Judson. J Am Ceram Soc[J], 2006, 85(3): 21.
4Schwetz K A, Vogt G. Process for the Production of Dense Sintered Shaped Articles of Polycrystalline Boron Carbide by Pressureless Sintering, U S Pat 4195066[P], 1980-03-25.